The Philosophic Grammar of American Languages, as Set Forth by Wilhelm von Humboldt / With the Translation of an Unpublished Memoir by Him on / the American Verb

The Biology, Physiology and Sociology of Reproduction / Also Sexual Hygiene with Special Reference to the Male

Text Book of Biology, Part 1: Vertebrata

Five Stages of Greek Religion

Christianity and Greek Philosophy / or, the relation between spontaneous and reflective thought / in Greece and the positive teaching of Christ and His / Apostles

Language / An Introduction to the Study of Speech